Chikungunya fever--re-emergence of an old disease.

Several large outbreaks of Chikungunya infections in the past decade have stimulated renewed interest in the Chikungunya virus. This special issue describes recent outbreaks of Chikungunya and discusses possible reasons for the re-emergence of this arbovirus; reviews the ecology and geographic expansion of its vector, the Asian tiger mosquito, Aedes albopictus; summarizes our current knowledge of the immune response to infection; and presents our understanding of pathogenesis based on research in animal models.